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Building a Retaining Wall

You want a cement pad on a slope?

How are you going to do that?” First thing’s first, a RETAINING WALL is in the works.

YUP, we are in the process of building our own!Have you ever decided you were going to build something and the looks you get from people say ‘WHAT? YOU CRAZY? WHY? Just get it done!’Yeah, we get those looks alot. HAHA..but let’s not forget the annoyances we’ve had along the way because we actually tried to get this one done.This retaining wall all started with a loose contract with patio contractors that fell through.If you missed all that, you can read that HERE.

Because of that, we decided we were going to build the retaining wall ourselves. We had watched the contractors construct a retaining wall just a couple months prior so we knew exactly the steps to take to build one. From there we drew out detailed cross-sections and diagrams to plan it out.Using simple math formulas, we figured out how much stone, aggregate, and blocks to purchase and how deep we should dig the trench for our local area.

If you want to draft out a retaining wall, use our previous post as a guide and template to plan out yours.I laid out our diagrams, including all the math formulas we used, to make it easier to get you started.You can read that DETAILED post HERE.Once we had the strategy, the whole family got started right away.

Digging The Trench

OK…..yeah, digging digging and more digging to get this! But that’s ok. Better for the kids than sitting inside playing fortnight all day.We dug a trench a little wider than the wall blocks. Look at the bullets below the collages for all the details and descriptions!!

After we dug the entire trench for the long back retaining wall, we turned the corner and dug only 2 feet in on the retaining wall sides.

The base block 1st layer will need to be completely buried on the sides of the retaining wall which will include 2 base blocks for our particular slope.

The rest of the length of the retaining wall sides will be blocks that step up underground.

On the sides of the retaining wall, Crush and run will butt up against the blocks as you step up.

Please refer to our PLAN and DIAGRAM post to understand why. Once you see the cross section of how a retaining wall is constructed on the sides, it will make more sense. No need to scroll up to that link….I put it HERE.

Adding Siltscreen

Dirt was tamped, flattened and completely leveled before adding the silt screen.

Silt screen went into the trench.This provides better drainage under the wall.I tried to take a picture of the silt screen for all of you but do you see what I did?I took a picture of the wrong side of the label.….the Spanish side!!! HA. Oops.Sorry about that!I didn’t see that until I was loading up all the pictures.Hopefully you will be able to recognize it in the store. We purchased it at Home Depot!

When adding the silt screen we put bricks on either side of the trench to hold it down so it wouldn’t cave in on us while we are working.Next….

Adding Crush And Run

We had the stone store deliver piles of stone on our driveway.We shoveled the crush and run into a wheel barrow and then poured the crush and run into the trench.

Don’t be deceived!Pouring crush on a slope may seem like it would be pretty easy until you fall and the wheel barrow almost topples you.HAHA….Maybe I am giving you too much imagery of our day here but you might want to be more careful than I!It can be very heavy and there were times we just shoveled it into the trench.

Tamping & Leveling C&R

YES, this is probably the hardest part of the whole project. COMPACTING AND LEVELING….Jiminy Christmas, our joints ached a little after this one. ha.

Every 2 inches of crush and run that we added, Ed compacted!!!You need to use a lot of force here.

Each 2 inch layer of crush and run also gets leveled.

This was repeated until we got up to 10 inches of crush and run in the trench.

Make sure it is completely level before the first layer of blocks go in.

Adding block

Once the trench was completely level, we added the first layer of base block into the trench. This first layer is critical to be level before any other layers of block get added on top.This actually took some time to perfect across 12 feet along that back trench.Not only does the entire length of block get leveled but the width of each block also has to be leveled.This was the most time consuming part of the retaining wall. Once we got it, the next layers went in faster and much more smoothly.

The entire length and width of the block in the trench got leveled.

When not level, blocks had to be removed and the tamping and leveling of crush and run needed to be repeated.

masonry adhesive was bought at the stone store.It is applied in between the block layers.

In the 3rd pic above, draining aggregate stone filled the gaps in between the block and the sides of the trench.

Adding Corner blocks

YAY our second layer is going in.Shown here are the corner blocks.

The specialty corner block is finished on 3 sides seen from 2 angles forming a corner.Please refer to the PLAN and DIAGRAM post for further explanation on corner blocks.. Don’t scroll up again for it…The link is right HERE.

Cutting masonry blocks and building wall SIDES

There were times that Ed had to cut the blocks to get it to fit.Wall block and corner block were both cut using this method that you see in the pic.

Stone aggregate filled in all of the pin holes and gaps around the blocks.

Here on the sides of the retaining wall (pic4) the crush and run butts up against the base block on the step ups.Once again the crush and run gets compacted but remains level to the adjacent block next to it. Refer to our PLAN and DIAGRAM post for better understanding for the sides of the retaining wall. No need to scroll up to that link….I put it HERE.

Adding Stone Aggregate

Once the retaining wall block became level with the slope, Geogrid fabric was placed on the ground on top of the slope to be sandwiched between the next layer of block on the retaining wall. You can see this geogrid fabric in the first pic below.Geogrid fabric ties the layers of aggregate and the wall together as one unit. Please refer to the steps in the collage.

Stone aggregate got poured on top of the geogrid mesh.

The aggregate gets completely spread on top of the slope using a rake and then tamped down.

Every 2 inches of aggregate that was added got compacted and leveled.

Once the stone aggregate filled up and became level with the retaining wall block, geogrid mesh was added AGAIN sandwiched in between the next layer of wall block

Stone Aggregate again was added one last time on top and tamped down

Using a mason’s line

Throughout the entire time as we were building this wall, starting with the first row above ground level, a mason’s line was used. This was critical in keeping the wall plumb.

Because there was no lip on the edge of the block to keep the block stacking with proper alignment, Ed used a masons line .

With every block layer that was added, he slid the mason’s line up the guides. This would ensure the retaining wall would not look like the Leaning Tower of Pisa. AH!!!

Adding Capstone

After the aggregate was all poured, tamped and leveled on top of the slope, the finale begins with adding the capstone.We were so excited to get to this stage!!! It’s a retaining wall!!!

Using adhesive, Ed added capstone on all 3 sides of the retaining wall.

The corners of the capstone needed to be cut at a 45 degree angle.Ed achieved this miter cut using an angle grinder.Because the capstone was at the very top and needed a finished look,he used the angle grinder to get a much more precise cut.

Ready for Concrete

WOOHOO…We finally made it here!The retaining wall is complete and totally ready for a cement pad to be poured on top of the stone aggregate.

I am so excited this wall is done…You just have no idea!And all before the freezing cold temperatures and smoldering fires with our wood-burning stove.This cement pad and retaining wall will be so perfect.If you haven’t been following along…um, yeah we are doing all this work to slap some piles of wood on it.HAHA. I like a nice neat woodpile ok!We can finally move on to pouring the concrete for the cement pad!

I’ve been wanting to do this for some time but with garden beds instead of the cement pad. Would all of the aggregate still be needed or could I just use the dirt from the dug out trench, plus any additional that may be needed to level the top layer?

I think you would still want that stone aggregate for drainage. We poured stone aggregate so that 4 inches of concrete could be poured on top and become level with the retaining wall cap stone surround. You would just use less aggregate and instead of pouring cement you would pour more dirt. Maybe 10 inches of dirt? Check into the height of how much dirt you would need. Good luck on your project.

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Hi there, I'm K. Rupp....an artsy type married to a DIY guy. K is for Kathleen and my husband is Ed. So......years ago when we got married, Kathleen + RUPP + Ed = KARUPPED! It has now evolved into this site! I'm so happy you are here! Read More…